After Re-Lamping that low bay in the gym of one of the schools i look after it got me thinking...How long have low bays been out for? These THORN EMI black gear tray low bays were definatly fitted in the early 80s. One thing i did notice is that they were MK15?SO does anyone know when the first low bays came out and what the looked like?

In Lighting Gallery there are some posted from the US, recessed square boxes, with A shaped 100W mercury lamps. That would be no later than 60's i think

As for what i seen myself, the square lowbays are new, before them there were quite a lot of other things abused as lowbays - highbays with undersized lamp, fluorescent packs, streetlights, floodlights....

I can think of one very old design, that might actually be a fixture meant to be a lowbay. It is about the size to barely fit a 125W merc in it, usually used with 125W merc (remote gear) or 200W incandescent. And it is threaded in a way that makes it go well with metal-pipe installations, especially attached to the cover of metal wiring boxes and such

The Thorn Lopak as a square box probably goes back no earlier than the mid 70's IMHO.With fittings, I notice that the MK numbers go up alot on Thorn fittings. Look at the Popular pack, it was on MK12 in the late 80's yet we all know the PP wasn't a nice slim batten throughout it's whole design